When starting roasting with a new machine or for those new to the roasting process, it is common to observe deformities in coffee beans during the roasting process. The two most frequent deformities are scorching and tipping.
To distinguish between these defects, it is sufficient to observe where the spots appear on the coffee. Scorching typically manifests as burnt areas on the flat surface of the coffee beans, while tipping presents as speckled spots. What exactly causes these deformities? The causes can be listed in the following order: high charge temperature, slow drum speed, and starting with a high flame level at the beginning of roasting. To address these issues, the charge temperature can be lowered, the drum speed increased, or the flame power kept low during the initial stages of roasting. Additionally, if the coffee beans are roasted for an extended period, cooling the drum can also be beneficial.
It is also crucial to ensure the cleanliness of the coffee beans throughout this process. It is recommended to always purchase green coffee beans from reputable and trustworthy sellers. By reviewing the entire process and implementing these measures, the likelihood of encountering bean defects will significantly decrease.